Airing Down BGF AT's

N / A · **Posted:** Wed Apr 11, 2007 7:54 am

does anyone here air down their AT's? If so what pressure do you run off road?

JJsTJ · **Posted:** Wed Apr 11, 2007 9:31 am

N / A wrote:

does anyone here air down their AT's? If so what pressure do you run off road?

15-20 PSI has worked fine for me.

N / A · **Posted:** Wed Apr 11, 2007 9:33 am

and what do you run in them on the road? the tire place told me 50psi

gopherbeats · **Posted:** Wed Apr 11, 2007 12:43 pm

I run mine at 20-25 off road.
I run them 35-40 on road.. any higher and my spleen starts writing letters of complaint because of the potholes...
If I know I will be doing a long highway run, I'll juice them up a little more to save gas.

N / A · **Posted:** Wed Apr 11, 2007 5:55 pm

man the BFG distriburtor told me not to go under 50, they said to use 50 if higher was too rough (on road that is)

jason thompson · **Posted:** Wed Apr 11, 2007 5:57 pm

50 psi is way to high for a KJ

Look around for the post that showed the chalk trick it works

what psi to run offroad will depeend on load range
I have L/R C on both jeeps but the KJ weighs more on the front than the TJ so I do not go down below 18psi on the front of the KJ
now on the TJ I run 16 psi at all 4 corners and I may go to 16 on the rear of the KJ

Now if they are L/R D you cold get away with lower psi say 16 front and rear
but bring out an air supply that can reseat a bead

Rock Lizard · **Posted:** Wed Apr 11, 2007 8:31 pm

When we had them on the wife's ZJ, I ran them at 30 on the street and 12 on the trail. Never had any problems, hooked up pretty dang good on the rocks for an AT. I really like the BFG AT/KO's for an AT, but I still prefer my Trxus MT's.

N / A · **Posted:** Wed Apr 11, 2007 8:47 pm

Rock Lizard wrote:

When we had them on the wife's ZJ, I ran them at 30 on the street and 12 on the trail. Never had any problems, hooked up pretty dang good on the rocks for an AT. I really like the BFG AT/KO's for an AT, but I still prefer my Trxus MT's.

I wanted Truxs but didn't want the 235 85 so my only other option was a 31*10.5 but I was told 15's woudn't clear the rotors...what are you using?

Rock Lizard · **Posted:** Wed Apr 11, 2007 9:18 pm

N / A wrote:

...what are you using?

A 1998 Jeep Grand Cherokee. :twisted:

Big D · **Joined:** Mon Jun 05, 2006 10:08 pm **Posts:** 349

Ah, the dreaded air pressure question. Here's my 2 cents.

I'm running 225/75 16 Mickey Thompson MTX. Load range D, so slightly higher than stock load range C.

As many I've been experimenting with everything from the max 65lbs which gives brutal onroad comfort, but quite good turnin, to 26 lbs (what I'm currently running) which gives a excellent onroad and good offroad ride.

At 65lbs, the front gained a good 1/2 to 3/4 inch in height. So for offroad this sounds good but I had to go so slow so as to keep my teeth from falling out that it was actually hampering my progress.

At 26 lbs, the amount of clearance I lost was quickly made up with speed and comfort.

Now, how did I arrive at this pressure for onroad driving. I tried a couple of techniques. One is to draw the chalkline across the tire and drive a few hundred yards in a straight line, and the other was to measure the difference between cold and warm air pressures. Ideally, someguys claim your pressure should rise about 4 psi. So, at those pressures, I'm getting full chalkline contact as well as an increase of 4psi from cold to hot temps.

Now, factory specs call for 33 psi for both front and back. You have to remember that's for a fully loaded vehicule at max load.

Next, I looked at certain various European makes with similar sized tires. An old S class Mercedes, weighs in at around 4000 lbs so it was pretty close. What they recommend was 26lbs for front and rear with 27 for max load (in the rear only). Where sustained speeds in excess of 160 kp/h are experiecenced for extended periods of time (autobahn) you should raise the pressure by 9 PSI. These pressure are for maximum comfort, and tread wear.

So, if you're running empty most of the time, it would make sense to reduce the pressures slightly (mainly at the back), and if you're driving very fast (which none of us in Jeeps should be anyway) you should increase them.

Anyway, that's my 2 cents worth on the topic.

kayadog · **Posted:** Thu Apr 19, 2007 8:57 am

On my XJ I've been very happy with 32 psi on road in my BFG AT ko's and 12-18psi in the sand depending on how soft it is.

Airing Down BGF AT's

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